Number and size of perigastric lymph nodes in human adults without gastric cancer

Distribution of Perigastric Station 4d Lymph Nodes in Vascularized Gastroepiploic Lymph Node Transfer: An Anatomic Study and Case Series

BACKGROUND

Vascularized gastroepiploic lymph node transfer (VGLNT) is a well-accepted surgical treatment for restoring physiological function in chronic lymphedema. However, the inclusion of substantial lymph nodes (LNs) in the flap remains uncertain. This study aimed to identify the anatomical basis for reliable flap harvest for VGLNT.

PATIENTS AND METHODS

The anatomy of perigastric station 4d LNs was studied in healthy cadavers (n = 15) and patients with early gastric cancer (EGC) (n = 27). The omentum was divided into three segments: proximal, middle, and distal from the origin of the right gastroepiploic vessels. The flap dimension, number, location, size of LNs, and caliber of the vessels were reviewed. Eight patients underwent VGLNT for upper/lower limb lymphedema.

RESULTS

The mean numbers of LNs in the proximal, middle, and distal segment were 2.5, 1.4, 0.5 in the cadavers, and 4.9, 2.7, 0.7 in the gastrectomy specimens, respectively. The proximal third included a significantly greater number of LNs than the distal third in the cadaveric (p = 0.024) and ECG (p = 0.016) specimens. A total of 95% of the LNs were located within proximal two-thirds of the flap from the vessel origin both in the cadavers (21.0 × 5.0 cm) and in the gastrectomy specimens (20 × 3.5 cm). In VGLNT, the transferred flap was 25.5 ± 6.9 × 4.1 + 0.7 cm in dimension, containing a mean number of 6.5 ± 1.9 LNs. At postoperative 6 months, the volumetric difference was significantly reduced by 22.8 ± 9.2% (p < 0.001).

CONCLUSIONS

This study provides a distinct distribution pattern of station 4d LNs. Inclusion of the proximal two-thirds of the flap, which carries majority of the LNs, is recommended for VGLNT.

Development and validation of a clinical cure marker based on negative lymph nodes for gastric cancer after gastrectomy

Objective

To explore lymph node (LN)-related derived indicators as clinical cure markers for gastric cancer (GC) after gastrectomy.

Methods

Data of resected GC patients were extracted from the SEER database and our own department. Propensity score matching (PSM) was used to balance the baseline differences between the clinical cure and the nonclinical cure groups. The area under the curve (AUC) and decision curve analysis (DCA) were used to choose the optimal marker, and survival analysis was used to validate the clinical value of the most effective marker.

Results

After PSM, the differences in age, sex, race, location, surgical type, and histologic type between the two groups were significantly reduced (all P > 0.05), and the AUCs of examined LNs (ELNs), negative LNs (NLNs), ESR (ELNs/tumor size), ETR (ELNs/T-stage), NSR (NLNs/tumor size), NTR (NLNs/T-stage), EPR (ELNs/PLNs) and NPR (NLNs/PLNs) were 0.522, 0.625, 0.622, 0.692, 0.706, 0.751, 7.43, and 7.50, respectively. When NTR was 5.9, the Youden index of 0.378 was the highest. The sensitivity and specificity were 67.5% and 70.3% in the training group and 66.79% and 67.8% in the validation group, respectively. DCA showed that NTR had the largest net clinical benefit, and patients with NTR greater than 5.9 had significantly prolonged overall survival in our own cohort.

Conclusion

NLNs, NTR, NSR, ESR, ETR, NPR and EPR can be used as clinical cure markers. However, NTR was the most effective, and the best cutoff value was 5.9.

Lessons Learnt from an 11-year Experience with Lymphatic Surgery and a Systematic Review of Reported Complications: Technical Considerations to Reduce Morbidity

Complications experienced during lymphatic surgery have not been ubiquitously reported, and little has been described regarding how to prevent them. We present a review of complications reported during the surgical management of lymphedema and our experience with technical considerations to reduce morbidity from lymphatic surgery. A comprehensive search across different databases was conducted through November 2020. Based on the complications identified, we discussed the best approach for reducing the incidence of complications during lymphatic surgery based on our experience. The most common complications reported following lymphovenous anastomosis were re-exploration of the anastomosis, venous reflux, and surgical site infection. The most common complications using groin vascularized lymph node transfer (VLNT), submental VLNT, lateral thoracic VLNT, and supraclavicular VLNT included delayed wound healing, seroma and hematoma formation, lymphatic fluid leakage, iatrogenic lymphedema, soft-tissue infection, venous congestion, marginal nerve pseudoparalysis, and partial flap loss. Regarding intra-abdominal lymph node flaps, incisional hernia, hematoma, lymphatic fluid leakage, and postoperative ileus were commonly reported. Following suction-assisted lipectomy, significant blood loss and transient paresthesia were frequently reported. The reported complications of excisional procedures included soft-tissue infections, seroma and hematoma formation, skin-graft loss, significant blood loss, and minor skin flap necrosis. Evidently, lymphedema continues to represent a challenging condition; however, thorough patient selection, compliance with physiotherapy, and an experienced surgeon with adequate understanding of the lymphatic system can help maximize the safety of lymphatic surgery.

Technical Challenges in "Micro" Lymph Node Identification during Vascularized Submental Lymph Node Flap Harvesting

Background:

The outcome of autologous lymph node (LN) transfer has depended on the number of LNs in the donor site. Unknown accuracy of the LN counting method has thrown some doubts on the reliability of the previous statistics. This study aimed to assess the accuracy of naked eye (NK) and stereo microscopy (SM) as tools for LN count.

Methods:

In total, 40 vascularized submental LN flaps were harvested from 23 fresh cadavers. The colored polymer was injected into the external carotid arteries before the harvest. LNs in each flap were counted by NK, SM, and histology in sequential order.

Results:

An estimated 175 LNs were confirmed, 4.4 ± 1.8 per flap. NK sensitivity was 33.7% compared with that of SM at 63.5%. Both methods missed all micro-lymph nodes (micro-LNs), contributing to 5.1% (9 nodes) of all LNs. Non-LN structures (647 negative counts) were composed of fat lobules, salivary gland lobules, and muscle fibers. NK specificity was 98.0%, compared with that of SM at 96.1%. SM showed a higher false positive rate at 14.3%, compared with NK at 7.4%. False positive counts were located mostly in Ib sublevel.

Conclusions:

NK and SM are imperfect tools for LN count due to poor sensitivity. If the method needs to be applied, points of considerations are (1) undetectable micro-LNs, (2) interposition of LNs with the digastric muscle and submandibular salivary gland, (3) confusion of LNs with lobules of salivary gland supplied by glandular artery or fat lobules supplied by lobular artery.

Technical details for harvesting gastro-epiploic lymph node flaps via mini-laparotomy incision

Laparoscopic harvest method to obtain gastro-epiploic lymph node flaps for lymphedema treatment has been previously described. In this article, the technical details of an alternative method - open approach via mini-laparotomy incision - for harvesting gastro-epiploic lymph node flaps and preparation of the flaps for the inset is presented. A total of 17 patients were included in this series of the mini-laparotomy approach. Blood loss was minimal during the surgery. The average duration of lymph node flap harvest was 65 min. The average length of hospital stay was 10 days. The period of the restricted diet was 1.5 days. The upper abdominal scar was acceptable, there were no postoperative hernia or bulging, and there were no complications related to bowel obstruction during the follow-up. The open approach harvest method via mini-laparotomy incision offers similar results to laparoscopic harvest method, and it is safe when applied with the right technique.

Multi-Compartment 3D-Cultured Organ-on-a-Chip: Towards a Biomimetic Lymph Node for Drug Development

The interaction of immune cells with drugs and/or with other cell types should be mechanistically investigated in order to reduce attrition of new drug development. However, they are currently only limited technologies that address this need. In our work, we developed initial but significant building blocks that enable such immune-drug studies. We developed a novel microfluidic platform replicating the Lymph Node (LN) microenvironment called LN-on-a-chip, starting from design all the way to microfabrication, characterization and validation in terms of architectural features, fluidics, cytocompatibility, and usability. To prove the biomimetics of this microenvironment, we inserted different immune cell types in a microfluidic device, which showed an in-vivo-like spatial distribution. We demonstrated that the developed LN-on-a-chip incorporates key features of the native human LN, namely, (i) similarity in extracellular matrix composition, morphology, porosity, stiffness, and permeability, (ii) compartmentalization of immune cells within distinct structural domains, (iii) replication of the lymphatic fluid flow pattern, (iv) viability of encapsulated cells in collagen over the typical timeframe of immunotoxicity experiments, and (v) interaction among different cell types across chamber boundaries. Further studies with this platform may assess the immune cell function as a step forward to disclose the effects of pharmaceutics to downstream immunology in more physiologically relevant microenvironments.

The "String of Pearls" technique for increased surface area and lymphedematous fluid drainage in right gastroepiploic-vascularized lymph node transfer: A report of two cases

We present our "String of Pearls" technique for upper and lower extremity lymphedema based off the right gastroepiploic artery. The entire laprascopically harvested omentum is placed through a longitudinal incision at the lymphedematous area, and anastomosed proximally, with additional distal venous outflow. This approach preserves the native lymphaticovenous architecture, distributes free lymphatic tissue along the axis of the extremity, and allows for scar release. The additional vein serves to restore bidirectional physiologic drainage inherent in the omentum and providing further lymphaticovenous drainage. We present two cases of upper and lower extremity lymphedema as a result of malignancy treated using this method. The first case was a result of breast cancer in a 55-year-old female with orthotopically placed omentum, and the second case a result of malignant nodular fasciitis in the distal lower extremity in a 56-year-old female with distally placed omentum. No complications occurred. At 3 months follow up, there is a 25% and 28% reduction in lower and upper extremity volume, respectively, with no recurrent cellulitis episodes. The safety and feasibility of placement of the entire omentum longitudinally with additional venous anastomosis are apparent. However, long-term studies are required.

Anatomic Study of Distribution, Numbers, and Size of Lymph Nodes in Mesorectum in Indians: A Autopsy Study

This study was conducted to find the number, size, and distribution of the lymph nodes in the mesorectum in fresh cadavers without rectal cancer in Indians and to compare fat clearance method versus manual dissection of lymph nodes in terms of efficacy of lymph node yield. Thirty fresh cadavers underwent total mesorectal excision (TME) by midline incision. TME specimen was divided transversely (upper, middle, and lower thirds), and then further divided radially into 4 equal areas and the right lateral, left lateral, and posterior areas were taken for lymph node harvesting. In the first 15 cases (group A), lymph nodes were dissected manually from each of 9 areas. Number and diameters of harvested nodes were noted, and specimens were histopathologically examined. In the next 15 cases (group B), fat clearing technique was used, and the procedure was repeated. Mean number of lymph nodes recovered per cadaver was 6.2 (SD = 1.3; range, 5 to 9, group A = 5.86 ± 1.24, group B = 6.60 ± 1.29, P = .126) and mean size of the lymph node was 2.1 mm (SD = 0.38; range, 2 to 8 mm). Size and numbers of nodes in all the areas were similar between the 2 groups except in lower third, where smaller nodes were identified in greater numbers in group B. Manual dissection is an effective technique for node harvesting after TME, except for very small nodes found in the lower third of mesorectum. Accurate pathological examination of TME specimen is mandatory to avoid understaging of disease.

Nano-imaging of the lymph network structure with quantum dots

Sentinel lymph node diagnosis contributes to operative strategy in cancer surgery. During lymph node metastasis, cancer cells first reach the sentinel lymph node (SLN) via lymph flow. To perform SLN biopsy effectively, it is important that cancer cells are detected with high sensitivity in SLN connected to the tumor site. Here we present a method to visualize a high-risk area in the SLN for lymph node metastasis with a high degree of accuracy. Quantum dots (QDs), bright fluorescent nanoparticles, were endoscopically injected into the gastrointestinal wall of pigs, and their signal was specifically detected in the SLN with a laparoscopic device. Single-particle imaging under a confocal microscope showed that the QDs were distributed heterogeneously in the SLN and that their distribution marked the inflow locus of afferent lymphatic vessels where lymph node metastasis begins. Moreover, we developed a method using cellular marker conjugated QDs that visualizes specific cells in SLNs, suggesting that this method can be applied for the detection of cancer cells in sentinel lymph nodes using tumor-specific-molecular conjugated QDs. These results show that our method might significantly increase the detection rate of cancer metastasis in SLNs.

Defining the lymph node burden in a Northern European population without malignancy: the potential effect of geography in determining a need for FNA?

Data from the USA suggest that morphological specificity is insufficient to permit an assumption of malignancy in nodal staging with endoscopic ultrasound (EUS). This may not hold true elsewhere as the background lymph node burden may vary in different geographic regions. We aimed to assess the prevalence and features of mediastinal and abdominal lymph nodes at EUS in a Northern European population without malignant disease. A total of 129 consecutive patients without malignant disease referred for radial EUS were prospectively evaluated for the prevalence and echo features of lymph nodes in the mediastinum and upper abdomen. Sixty-two percent of patients had mediastinal lymph nodes and 17% had abdominal nodes at EUS. A mean of 1.4 (standard deviation 1.3, range 0-8) nodes were found per patient. No celiac nodes were seen. The majority of detected nodes were 0.5 cm or less in short axis, had oval shape, centrally echogenic pattern, and indistinct borders. The most common node locations were the subcarinal and paraesophageal areas, and the hepatoduodenal ligament. In multivariate analysis mediastinal lymphadenopathy was related to body mass index and abdominal lymphadenopathy to acute pancreatitis. The occurence of mediastinal lymphadenopathy is markedly lower in Northern Europeans than reported for US patients. Celiac nodes are extremely rare in patients without malignancy. The majority of nodes have a width of 0.5 cm or less, have oval shape, centrally echogenic pattern, and indistinct borders. The characterization of the background lymph node burden may improve the selection of lymph nodes for fine needle aspiration.

Lymph node counts in indians in relation to lymphadenectomy for carcinoma of the oesophagus and stomach

OBJECTIVE

Systemic lymphadenectomy for carcinoma of the oesophagus and stomach is increasingly accepted as effective surgical treatment. A review of available literature reveals a great variety in the number of lymph nodes removed during standard lymphadenectomy. The present study was conducted to find the normal number of lymph nodes in the Indian population in relation to lymphadenectomy for oesophageal and gastric carcinoma.

METHODS

Lymph nodes situated at stations 1-16, relevant to lymphadenectomy for gastric cancer, were removed by lymph node dissection according to the recommendations of the Japanese Research Society for Gastric Cancer and those at the 22 stations, relevant to lymphadenectomy in oesophageal cancer, were removed according to the International Society for Diseases of the Esophagus recommendations in 10 cadavers without a history of any abdominal pathology or haematological lymphatic disease. Nodes were cleared by dissolving fatty tissue. All lymph nodes were histologically confirmed and the diameter of each lymph node was recorded.

RESULTS

An average of 52.0 nodes (range, 37-78 nodes) was found at Stations 1-16, while an average of 183.6 nodes (range, 118-234 nodes) was found at the 22 stations. These numbers are higher than those in the literature.

CONCLUSION

This anatomical study addresses the dual issues of determining the number of dissectable lymph nodes in a particular population as well as assessing the quality of nodal dissection by providing quantitative surgical guidelines.

Relationship between nodal stage and the number of dissected perigastric nodes in gastric cancer

To evaluate the rationality of the current nodal staging system in gastric cancer, we retrospectively analyzed 152 patients with perigastric node involvement localized to a single station, in whom the route of metastasis to distant nodes was limited. No significant differences in pathology or survival were observed between patients with stage n1 and those with stage n2-3 nodal involvement, but the mean (standard deviation) number of perigastric nodes dissected was 22.6 (12.6) in those with stage nl involvement and 18.5 (9.5) in those with stage n2-3 involvement (P = 0.04). When perigastric node involvement was localized to station 3, the mean number of dissected station 3 nodes was 7.7 (4.2) in nl patients and 5.3 (2.8) in n2-3 patients (P = 0.04). This tendency was also observed in patients with perigastric node involvement limited to either station 1 (P = 0.08) or station 6 (P = 0.11). Thus, patients with fewer perigastric nodes may have more lymphatics that bypass perigastric nodes and empty directly into distant nodes, increasing the likelihood of skip metastases. The number of positive nodes, affected to a lesser degree by lymphatic distribution than the location of positive nodes, should be incorporated into the staging criteria.